First, use the matching DSLR Project Preset.
Then, when you have edited the Project, just Share the Timeline to the desired format. You can reduce the Frame Size (in most options), and also the Bit-Rate, to reduce the file size and also the quality, as needed.
Thanks for the info - sounds straight forward. Not sure why I didn't notice it myself. Just switched from Vegas Movie Studio HD to Premiere Elements 10 so a little tough getting started. Have the Adobe Premiere Elements 10 Classroom in a Book which is a great help.
More reading to get you started...
Steve's Basic Training Tutorials... steps are the same for several versions
Right click PDF link in the upper right corner and select to save to your hard drive
I understand. Some NLE (Non Linear Editor) programs do things slightly differently.
As Adobe uses native files for Import and editing, the Project Presets are important, to get things going correctly. The output does not come into play, until after the editing, and then the desired delivery decides that.
The only exception is with a Still Image ONLY SlideShow, with NO Video. Then, the delivery is the main consideration.
Good luck, and John T's recs. for Steve Grisetti's Basic Training and his Learning Series, are very good ones, and well worth the read.